Where are influence and mapping settings of a texture saved?
You're right if you switch the Properties View to Datablocks you can examine the datastructure. 

You find the per slot settings (Texture Layers) under /Materials/MaterialName/Textures /TextureName.
Each texture slot has its own settings.



How the different settings influence the resulting material is controled by the influence sliders of the checked properties and the Blend Mode setting.